1. Field of the Invention
This invention relates to material for use in spacecraft parts which averts degradation of the surfaces caused by oxygen interaction.
2Description of the Prior Art
The successful flight of the Space Shuttle in the low earth orbit (altitude of about 100.about.1000 km) has clearly contributed to today's thriving spacecraft technologies including the construction of space stations, in the low earth orbit. Such technological development is nevertheless faced with difficult problems: as discussed in J. Spacecraft and Rockets, Vol. 23 (1986), pp. 501 to 511, a major component of the atmosphere in this altitude (low earth orbit) is the oxygen atom. These oxygen atoms, impacting on the atmospherically exposed surfaces of the spacecraft navigating in the orbit, cause a severe degradation of material used in the surfaces of the spacecraft parts.
More specifically, 23rd Aero. Sci. Meet., paper No. 85-0415 (1985) discloses the result of a flight test conducted to explore degradation, caused by the oxygen interaction, of material used in spacecraft parts and confirmed a degradation, i.e., a loss of the surface layer, of such material as FRP (fiber reinforced plastic), including CFRP and the like which were traditionally used in the spacecraft parts. Therefore, use of such materials for the spacecraft parts for a prolonged use (from several months to several decades), including space stations being developed presently or scheduled to develop in future, is unfeasible.
The above study also argues that, during several tens of hours of test flights, such commercial trade marks as Kapton and Miller, traditionally used in solar battery panels, sustained losses of as much as approximately 10 .mu.m of the surface layer. Again, this is indicative of problematic use of traditional materials in the solar battery panels to be loaded in the spacecraft designed for a prolonged use in the orbit.
Further, it is also concluded in the above study that, as a result of those test flights, such metallic materials as silver and osmium sustain a severe degradation of the surface layer, including loss of the surface layer. These materials, currently used in exposed wire placed on the interconnecting part of a solar battery mounted on a spacecraft, would be unlikely to be used in the exposed construction parts of the spacecraft designed for the prolonged use in the orbit.